Grout does a lot more than fill the gaps between your tiles. It seals out moisture, prevents mould, and holds your tiled surfaces together. But over time, even the best grout starts to show its age. Here are 10 signs it’s time to call in the professionals.
1. Discolouration That Won’t Budge
If your grout has turned from white or grey to brown or black and regular cleaning no longer helps, the staining has penetrated deep into the porous surface. Professional restoration can restore the original colour or regrout entirely.
2. Cracked or Crumbling Grout
Cracked grout is more than an eyesore — it’s an open door for water to get beneath your tiles. Once moisture reaches the subfloor, you’re looking at costly structural repairs. Regrouting stops the damage before it spreads.
3. Missing Grout Lines
If you can see gaps where grout used to be, water is already getting through. This is especially dangerous in wet areas like showers and around baths.
4. Mould or Mildew Growth
Black or green mould growing along grout lines isn’t just ugly — it’s a health hazard, particularly for those with respiratory conditions. Surface mould sprays rarely solve the root cause. Professional cleaning and sealing does.
5. Loose or Hollow-Sounding Tiles
Tap your tiles. If they sound hollow, moisture has likely gotten underneath and compromised the adhesive. Failed grout is often the entry point.
6. Water Stains on Ceilings Below Tiled Areas
Water stains appearing on ceilings or walls below a bathroom are a clear sign that grout failure is allowing water to penetrate. Act fast to prevent structural damage.
7. Grout That’s Darker in Some Areas
Patchy discolouration often indicates moisture is trapped inside the grout. This is an early warning sign of water infiltration.
8. Efflorescence (White Powdery Deposits)
That chalky white residue on your tiles or grout is called efflorescence. It’s caused by water carrying mineral salts to the surface as it evaporates — a sign of ongoing moisture movement through your substrate.
9. Grout That’s Soft or Sandy to the Touch
Healthy grout is hard. If yours crumbles when you scratch it or feels soft and sandy, the grout has degraded and needs replacing.
10. It’s Been More Than 5 Years Since Your Last Restoration
Even grout that looks okay benefits from professional deep cleaning and resealing every few years. Prevention is always cheaper than restoration.
Book a Professional Assessment
Not sure how bad it is? The Grout Guy offers expert assessments across New Zealand. We’ll give you an honest appraisal and a no-obligation quote. Get in touch today.